Function window [src]

Returns an iterator with a sliding window of slices for buffer. The sliding window has length size and on every iteration moves forward by advance. Extract data for moving average with: window(u8, "abcdefg", 3, 1) will return slices "abc", "bcd", "cde", "def", "efg", null, in that order. Chunk or split every N items with: window(u8, "abcdefg", 3, 3) will return slices "abc", "def", "g", null, in that order. Pick every even index with: window(u8, "abcdefg", 1, 2) will return slices "a", "c", "e", "g" null, in that order. The size and advance must be not be zero.

Prototype

pub fn window(comptime T: type, buffer: []const T, size: usize, advance: usize) WindowIterator(T)

Parameters

T: typebuffer: []const Tsize: usizeadvance: usize

Example

 test window {
    {
        // moving average size 3
        var it = window(u8, "abcdefg", 3, 1);
        try testing.expectEqualSlices(u8, it.next().?, "abc");
        try testing.expectEqualSlices(u8, it.next().?, "bcd");
        try testing.expectEqualSlices(u8, it.next().?, "cde");
        try testing.expectEqualSlices(u8, it.next().?, "def");
        try testing.expectEqualSlices(u8, it.next().?, "efg");
        try testing.expectEqual(it.next(), null);

        // multibyte
        var it16 = window(u16, std.unicode.utf8ToUtf16LeStringLiteral("abcdefg"), 3, 1);
        try testing.expectEqualSlices(u16, it16.next().?, std.unicode.utf8ToUtf16LeStringLiteral("abc"));
        try testing.expectEqualSlices(u16, it16.next().?, std.unicode.utf8ToUtf16LeStringLiteral("bcd"));
        try testing.expectEqualSlices(u16, it16.next().?, std.unicode.utf8ToUtf16LeStringLiteral("cde"));
        try testing.expectEqualSlices(u16, it16.next().?, std.unicode.utf8ToUtf16LeStringLiteral("def"));
        try testing.expectEqualSlices(u16, it16.next().?, std.unicode.utf8ToUtf16LeStringLiteral("efg"));
        try testing.expectEqual(it16.next(), null);
    }

    {
        // chunk/split every 3
        var it = window(u8, "abcdefg", 3, 3);
        try testing.expectEqualSlices(u8, it.next().?, "abc");
        try testing.expectEqualSlices(u8, it.next().?, "def");
        try testing.expectEqualSlices(u8, it.next().?, "g");
        try testing.expectEqual(it.next(), null);
    }

    {
        // pick even
        var it = window(u8, "abcdefg", 1, 2);
        try testing.expectEqualSlices(u8, it.next().?, "a");
        try testing.expectEqualSlices(u8, it.next().?, "c");
        try testing.expectEqualSlices(u8, it.next().?, "e");
        try testing.expectEqualSlices(u8, it.next().?, "g");
        try testing.expectEqual(it.next(), null);
    }

    {
        // empty
        var it = window(u8, "", 1, 1);
        try testing.expectEqualSlices(u8, it.next().?, "");
        try testing.expectEqual(it.next(), null);

        it = window(u8, "", 10, 1);
        try testing.expectEqualSlices(u8, it.next().?, "");
        try testing.expectEqual(it.next(), null);

        it = window(u8, "", 1, 10);
        try testing.expectEqualSlices(u8, it.next().?, "");
        try testing.expectEqual(it.next(), null);

        it = window(u8, "", 10, 10);
        try testing.expectEqualSlices(u8, it.next().?, "");
        try testing.expectEqual(it.next(), null);
    }

    {
        // first
        var it = window(u8, "abcdefg", 3, 3);
        try testing.expectEqualSlices(u8, it.first(), "abc");
        it.reset();
        try testing.expectEqualSlices(u8, it.next().?, "abc");
    }

    {
        // reset
        var it = window(u8, "abcdefg", 3, 3);
        try testing.expectEqualSlices(u8, it.next().?, "abc");
        try testing.expectEqualSlices(u8, it.next().?, "def");
        try testing.expectEqualSlices(u8, it.next().?, "g");
        try testing.expectEqual(it.next(), null);

        it.reset();
        try testing.expectEqualSlices(u8, it.next().?, "abc");
        try testing.expectEqualSlices(u8, it.next().?, "def");
        try testing.expectEqualSlices(u8, it.next().?, "g");
        try testing.expectEqual(it.next(), null);
    }
}

Source

  pub fn window(comptime T: type, buffer: []const T, size: usize, advance: usize) WindowIterator(T) {
    assert(size != 0);
    assert(advance != 0);
    return .{
        .index = 0,
        .buffer = buffer,
        .size = size,
        .advance = advance,
    };
}  